From bioclimatic indices to soil composition and training system. Rationalizing the drivers of wine’s sense of place in the Valpolicella region

The ability of a wine to express a ‘sense of place’, namely a connection between wine's perceived characteristics and its place of origin, is a key feature of wines from iconic productive regions. This research investigates the influence of bioclimatic indices, altitude, soil composition, and vineyard training systems on the enological parameters and aroma composition of Corvina grapes and wines within the Valpolicella region. This study aims to provide a comprehensive understanding of how these factors shape grape and wine characteristics across different climatic conditions and aging processes, leading to the occurrence of specific wine chemical profiles supporting the expression of wine's sense of place. A key aspect of this research was the classification of the Valpolicella region into distinct climatic zones using bioclimatic indices such as the Huglin Index (HI), Biologically Effective Degree Days (BEDD), and Growing Degree Days (GDD), revealing the presence of large portions classified as warm viticultural areas, but also of cooler vineyard locations. A predictive model was developed to estimate these indices across a selection of vineyards from which grapes and wines were obtained during two vintages. r. Among the geographical variables, altitude emerged as the most influential factor in determining vineyard climatic conditions, with clear distinctions observed between lower and higher-elevation vineyards. These climatic fluctuations influenced grape ripening patterns, nitrogen availability, and overall grape composition, highlighting the importance of site-specific climatic conditions in viticultural management. The second part of this research examined how altitude and climatic conditions (primarily temperature) affect enological parameters, grape composition, and the volatile aroma profile of Corvina young wines obtained from the selected vineyards. Warmer climatic zones (classified as “very warm” HI, BEDD Group 5, and GDD Region V) and lower-altitude vineyards exhibited higher pH values, increased maturity indices, and yeast assimilable nitrogen (YAN) concentrations, which significantly influenced fermentation performance and the production of aroma compounds. Conversely, vineyards at higher altitudes (above 300 m a.s.l.) retained higher acidity and exhibited lower nitrogen availability, which impacted both fermentative and varietal aroma compounds. In young wines, acetate esters, and fatty acid ethyl esters were more abundant in warmer zones, leading to an enhancement of fruity and floral aromatic attributes. The correlation between YAN concentrations and ester formation suggests that nitrogen availability plays a key role in modulating the aroma profile of Corvina wine. However, in colder zones and high-altitude vineyards, higher concentrations of benzenoids and certain norisoprenoids were observed, contributing to more complex aromatic attributes such as vanilla, pine, and mint-like notes. The third chapter of this study evaluated how different soil types influence grape composition, young wine, and aged wine characteristics. Two complementary approaches were applied: (i) a broad regional analysis based on soil classifications from ARPAV (Agenzia Regionale per la Prevenzione e Protezione Ambientale del Veneto) and (ii) a detailed investigation on wines from three contiguous vineyards having the same climatic indices but different soil types. Colluvial soil, characterized by higher organic matter and nutrient content, exhibited increased concentrations of terpenes, fatty acids, and alcohols while displaying reduced levels of the benzenoid compound ethyl vanillate. In the following chapter of this research, the role of the two main training systems present in Valpolicella (Guyot vs. Pergola) in modulating enological parameters and aroma compound development in Corvina wines was investigated. In cooler zones, the Guyot system promoted higher concentrations of terpenes and norisoprenoids, particularly linalool, β-damascenone, and vitispirane, which are associated with floral and fruity aromas. This suggests that the Guyot system may enhance the aromatic complexity of wines in cooler environments. Conversely, the Pergola system favored the accumulation of benzenoid compounds, including methyl vanillate and benzyl alcohol, which contribute to vanilla and balsamic notes. These differences suggest that vineyard management practices, including training systems, play a crucial role in defining the sensory characteristics of Corvina wines, particularly under varying climatic conditions. Finally, the relationship between wine aging and the expression of chemical patterns related to wine's sense of place was investigated. The results revealed the diversity of aroma aging patterns associated with the place of vineyard origin. In particular, cooler/higher altitude vineyards were associated with peculiar terpene development patterns with a greater contribution of cyclic and bicyclic minty terpenes, whereas warmer/lower altitude vineyards were associated with accumulation of sulfur compounds played a more dominant role in shaping the aged wine’s aromatic complexity.